Contraction is the coalescence of two adjacent vowels into a long vowel or a diphthong. It is one of the possible strategies for eliminating hiatus (Diphthongization; Synizesis). In Ancient Greek contractions ensued from loss of intervocalic /s/, /j/ and /w/. The term ‘contraction’ refers to coalescence of vowels word-internally. For the same phenomenon in word junctures, see Crasis.

Similar vowels coalesce into the corresponding long vowel: *kré…